$OpenBSD: patch-src_ptlib_unix_channel_cxx,v 1.1 2017/05/07 20:48:29 espie Exp $
--- src/ptlib/unix/channel.cxx.orig	Fri Apr 28 01:43:53 2017
+++ src/ptlib/unix/channel.cxx	Fri Apr 28 01:44:01 2017
@@ -36,6 +36,7 @@
 
 #include <ptlib.h>
 #include <sys/ioctl.h>
+#include <unistd.h>
 
 
 #include "../common/pchannel.cxx"
